Wireless communication networks facilitate communications with mobile or wireless user equipment (“UE”) (often referred to as mobile subscribers, remote stations or terminals). UE may include cordless phones, cellular phones, satellite phones, pagers, computers, personal data assistants (“PDAs”), entertainment devices, combined function devices, etc. The network equipment and UE have been modified to use feedback information provided by the UE to adjust future communications with the UE in order to improve quality and throughput. One type of feedback information that is often used is referred to as channel quality information (“CQI”) and may include information regarding the quality of the transmission channel. The UE measures the channel quality and provides feedback information to the network equipment. The network equipment uses the feedback information for many purposes, such as: selecting which UE to transmit data to (channel-dependent scheduling), selecting transport format for that UE (link adaptation) and power-setting (also some kind of link adaptation).
Unfortunately, the feedback information actually reported by the UEs cause its own problems. Specifically, the UEs cannot be trusted to report accurate feedback information. In fact, some current feedback information (e.g., CQI measurements) standards, such as WCDMA (a code division multiple access (“CDMA”) standard issued by the 3d Generation Partnership Project (“3GPP”)), allow vendors to produce UE's that report inaccurate CQI estimates. These unreliable CQI reports are harmful to network performance in several ways. For example, unreliable feedback information may cause a significant reduction in network capacity. In addition, unreliable CQI estimates can cause serious problems when channel-dependent scheduling is used. With channel dependent scheduling, the scheduler typically favors UE with a high reported CQI (i.e., a UE that reports a high CQI is more likely to be scheduled). If the CQI reports are unreliable, a channel-dependent scheduler will typically select the UE that overestimate their channel condition. This means that even if the reported CQI's are not initially biased, the CQI seen “after scheduling” will be predominately overestimated.
Moreover, UE that reports a larger CQI than what is motivated by the actual radio conditions may not necessarily suffer from low throughput since retransmissions are typically prioritized in the scheduling and the higher BLER may very well be compensated by being scheduled for transmission more often. While this may be beneficial for the user owning that UE, it results in worse performance for other users and worse overall performance (lower system throughput), both due to inefficient link adaptation and due to inefficient scheduling. As a result, especially from the network perspective, it is important to protect the network from UEs that report erroneous CQI. In particular, it is important to protect the scheduler from favoring UEs with too high reported CQI. Accordingly, there is a need for a method, apparatus and system for handling unreliable feedback information in a wireless network.